The holiday branched from the Roman holiday Lupercalia, which was a fertility celebration observed on February 15. Pope Gelasius I recast the pagan celebration to be a Christian feast day and dedicated February 14 to be St Valentine's Day. There were 3 early Catholic popes known to have the name St. Valentine, all 3 of which are said to have been martyred on February 14.
Throughout history the holiday evolved. By the 1800's giving homemade cards and gifts became customary in England, this practice became common in the United States in the 1850's and has grown since.
Valentine's Arrangements are normally symmetrical arrangements. They often contain hearts and are normally made of roses or lilies. A red, pink, and white color scheme is common. Price depends on the florist and size of the arrangement but normally range $20 and up.